This Asthma Clinical Research Network (ACRN) grant application involves three investigators who have extensive experience in multicenter asthma investigation. The areas of research expertise that will be brought to the ACRN include adult and pediatric investigation, allergy and immunology, pulmonology, pharmacology, chronobiology, steroid and beta-2 agonist receptor knowledge, airway inflammation, morphometrics, infection, physiology, and patient care. The two research protocols are potentially of great importance to the understanding of asthma pathophysiology and patient care. Protocol 1 will determine the link between chronic infection (Mycoplasma pneumoniae and Chlamydia pneumoniae) and chronic asthma. In a pilot study, we have shown that approximately 50% of patients with asthma exhibit evidence of M. pneumoniae or C. pneumoniae in their airways, and respond to treatment with a macrolide antibiotic. However, evaluation and extension of these observations in large multi-center trials are critical, if we are to potentially identify a new asthma phenotype, and thus affect therapy of asthma. Therefore, we propose to evaluate these patients with both a macrolide antibiotic and an inhaled corticosteroid (ICS) in subjects (+) and (-) for these bacteria. As we have been interested in corticosteroid responsiveness for many years, Protocol 2 will evaluate biomarkers to predict ICS responders (good, marginal, and poor) as well as determining why these different responses occur. This protocol is an extension of our own work, and work through ACRN with Denver as the lead center. Additive therapy, long-acting beta-2 agonists and anti-lgE, will be studied to determine if either or both improve responses to ICS. The ability to predict who will and will not respond to corticosteroids and additive therapy will greatly improve our ability to treat asthma effectively.